Mickey summons the Doctor and Rose to Deffry Vale High School, which he
believes has been infiltrated by aliens. Posing as a teacher, the Doctor
encounters abnormally intelligent students, a peculiar lunch programme,
and the sinister headmaster, Lucas Finch. But the Doctor isn't the only
person suspicious of Deffry Vale: also investigating the school is a
journalist by the name of Sarah Jane Smith...

Production

In the fall of 2003, executive producer Russell T Davies produced a
pitch document for the new Doctor Who series. One element of this
outline which did not survive into production was the suggestion that
the Doctor's robot dog, K·9 -- first introduced in 1977's The Invisible Enemy -- might again feature in
the revived series. K·9 had been extremely popular with young viewers;
even after then-producer John Nathan-Turner decided to remove him from
Doctor Who (with Warriors' Gate in
1981), his appeal had inspired the creation of a spin-off show entitled
K·9 And Company, although only a pilot episode was ever
aired.

Another idea which occurred to Davies at an early stage in the
development of Doctor Who was to bring back one of the Doctor's
former companions. Davies largely preferred to avoid dwelling on the
programme's lengthy history, but saw this concept as a way to shed a new
dimension on the fate of those who travel with the Doctor. Davies
initially thought that this proposal might be feasible should Doctor
Who survive into a third season. By early 2005, however, he had had
a change of heart and intended to position the story late in the series'
sophomore season.

Elisabeth Sladen was afraid that she was being invited
back to Doctor Who for a throwaway cameo

The returning character Davies wanted to feature in the adventure was
Sarah Jane Smith. Arguably Doctor Who's most iconic companion,
Sarah Jane had been portrayed by Elisabeth Sladen from 1973's The Time Warrior to 1976's The Hand Of Fear, spanning the regeneration
from Jon Pertwee's Third Doctor to Tom Baker's Fourth. Sladen had
continued to be associated with the character, chalking up appearances
in K·9 And Company, the twentieth-anniversary special The Five Doctors, the mid-Nineties radio plays
The Paradise Of Death and The Ghosts Of N-Space alongside
Pertwee, and several Sarah Jane Smith audio adventures from Big
Finish Productions in 2002 (with more then in the planning stages for
2006).

Sladen was contacted by the Doctor Who production office early in
2005 about appearing in the series, and was immediately apprehensive,
fearing that she was being invited back for a throwaway cameo. However,
after meeting with Davies and producer Phil Collinson, Sladen was
delighted to learn that Sarah would be the focal point of the adventure,
and portrayed in a manner which coincided with her own vision of how
Sarah Jane would have evolved after leaving the Doctor.

At this stage, the Sarah Jane story was entitled “Old
Friends”, and was intended to air late in the 2006 season. Davies
assigned scripting duties to Toby Whithouse, the creator of medical
comedy/drama No Angels. Whithouse had gotten his start in the
industry as an actor, appearing in shows such as Holby City and
films including Bridget Jones's Diary and Shadowlands
before taking up writing. Because Sarah Jane had been given K·9 Mark III
in K·9 And Company (the Mark I and Mark II versions having
remained with previous companions Leela and Romana, respectively),
Whithouse was also asked to incorporate K·9 into the storyline.

Whithouse initially struggled to find a plot on which to hang the Sarah
Jane material. Finally, Whithouse developed a treatment entitled
“Black Ops” which involved alien activity in a rural village
and a nearby army base. Davies liked elements of Whithouse's proposal,
but was concerned that the army base setting would force the writer to
jump through too many storytelling hoops. Instead, Davies suggested
shifting the adventure's locale to a comprehensive school; even as a
boy, Davies had harboured fantasies of the Doctor showing up in class
disguised as a teacher, and had used the setting himself in the 1991
telefantasy serial Dark Season. The school environment suggested
the inclusion of the chips subplot, drawing on the recent controversy
over school menus incited by the 2005 documentary series Jamie's
School Dinners. Around this time, it was decided that Whithouse's
script would air third in the season's running order, and so the writer
was asked to incorporate Mickey Smith into the plot, with the character
becoming a member of the TARDIS crew at its conclusion.

As a boy, Russell T Davies had dreamt of the Doctor
showing up in class disguised as a teacher

With its setting now finalised, the adventure became known as School
Reunion. The headmaster was called Hector Finch until it was learned
that there was a real teacher by that name; he was rechristened Lucas
Finch. Similarly, the aliens were initially Krillians, but when it was
discovered that the name was already trademarked, they became
Krillitanes. Their physical appearance changed greatly during the
episode's development -- originally they were all winged but otherwise
human, but later it was decided that most of them would be realised as
purely extraterrestrial computer-animated creations (whose appearance
was based loosely on descriptions of the mythical Harpies), while Finch
himself would display no overtly alien characteristics at all.

The appearance of K·9 Mark IV at the story's end was also omitted from
early drafts. The introduction of a rebuilt version of the character was
requested by K·9's cocreator, Bob Baker (who had long been planning a
K·9 cartoon spin-off). However, Davies had already asked Whithouse to
incorporate such a scene into his script. The Doctor Who
production team, meanwhile, had secured the services of John Leeson to
provide the voice of the robot dog. Leeson had had two stints voicing
K·9 during his original tenure on Doctor Who, and had returned to
the role on many occasions since, including K·9 And Company, The Five Doctors, the 2003 BBC webcast version
of Shada alongside Paul McGann's Eighth
Doctor, and the Gallifrey audio series from Big Finish
Productions beginning in 2004.

School Reunion was originally planned to be part of the season's
second production block, but was subsequently added to Block One when Tooth And Claw had to be delayed due to
scripting issues. As such, School Reunion was directed by James
Hawes alongside The Christmas Invasion
and New Earth. Two schools were chosen
to represent areas of Deffry Vale High. The first was Fitzalan High
School in Leckwith, Cardiff, where filming took place on August 23rd and
24th. Unfortunately, the K·9 prop (a rebuilt and motorised version of
the lightweight prop used in the Seventies) proved no more reliable than
earlier versions, moving only with difficulty over certain surfaces. In
addition, in the climactic sequence in the kitchen, K·9's eyepiece was
made to flash in time with his lines. This was out of keeping with the
way the robot dog had been portrayed in the past, and when Collinson
learned of it upon his return from a holiday, he ordered that the
practise cease for the rest of K·9's scenes.

The K·9 prop proved no more reliable than earlier versions
used in the 1970s

The confrontation between the Doctor and Finch was originally scripted
to happen in the school gymnasium but was moved to the pool, which Hawes
felt served as a more dynamic setting. Similarly, the TARDIS was
intended to be hidden in a supply closet, but its discovery by Sarah
Jane was shifted to the gym. Also taped at Fitzalan was material in the
playground and the cafetaria.

The major location for School Reunion was Duffryn High School in
Newport; shooting there was planned to begin on August 25th and continue
until September 2nd, omitting only the 28th. Many Duffryn students were
bussed in to be used as extras at both Fitzalan and their alma mater.
Unfortunately, the production block continued to fall behind schedule
during the shoot -- something which had already plagued Hawes and his
team during work on The Christmas
Invasion, which had largely been filmed first -- and it quickly
became clear that an additional day would be needed. Matters were not
helped on September 2nd when work on the scene in which Mickey crashes
the car into the front of the school -- actually a false porch
constructed by the BBC -- was held up by the discovery of asbestos in
Duffryn's genuine structure. The delays forced the abandonment or
simplification of some sequences, notably a time-lapse shot of the
school corridors to bridge the daytime and nighttime material.
Ultimately, an extra day of filming was held at Duffryn on September
6th.

The 7th was planned to feature the concluding shots of Sarah Jane
entering the TARDIS. This had been written as taking place in the ruins
of Deffry Vale, and Hawes' team had negotiated the use of a partly
torn-down British Telecom building for the recording. At short notice,
however, it was learned that the structure had since been completely
demolished, and so the shots were instead filmed in Newport's Belle
View Park, the implication being that the Doctor has moved the TARDIS
since the destruction of Deffry Vale. The K·9 prop used in this scene
was a refurbished version of the original radio-controlled prop built
for The Invisible Enemy.

The rest of the day was spent at Da Vinci's Coffee Shop in Newport for
scenes in the cafe. The TARDIS sequence was filmed at Unit Q2, Doctor
Who's regular studio space in Newport, on September 8th. Cast and
crew then returned to Da Vinci's, this time to shoot exteriors;
unfortunately, the night was hampered by the presence of several unruly
drunks. The same day, model work of the explosion was recorded at the
BBC Model Unit in London. This was the final filming ever undertaken by
the Unit, which was subsequently disbanded by the BBC.

The BBC Model Unit was disbanded after completing its
work on School Reunion

The last scene enacted for School Reunion was Mickey in the
cyber cafe, taped in Unit Q2 on October 8th. A similar setting was
revisited when Noel Clarke returned to film the episode's
TARDISode on January 31st, 2006 at Enfys Television Studios in
Cardiff. The 50-second piece was written by Gareth Roberts (as with the
other TARDISodes) and concerned Mickey phoning Rose to alert her
to the strange goings-on at Deffry Vale.

Several moments were trimmed or excised from School Reunion in
editing. Banter between Kenny, Melissa, Luke and Faisal prior to the
Doctor entering the classroom in the teaser -- which would have fleshed
out the children's characters -- was cut. Later in the same scene, the
Doctor's questions to Milo would have actually made him collapse,
prompting the Doctor to bring him to the school nurse (another
Krillitane); this was still alluded to in Wagner's dialogue with
Melissa. The Krillitanes eating the hermetically-sealed rats was
removed, and instead replaced by a voiceover explanation by the Doctor.
Another voiceover was used to truncate the scene in which Kenny deduces
that the fire alarm will disorient the Krillitanes.

Meanwhile, the return of Sarah Jane Smith was regarded so highly by the
Doctor Who production team that discussions soon ensued about
basing a new spin-off series around the character. Finally, on September
14th, it was announced that The Sarah Jane Adventures would air
beginning in early 2007, with Sladen once again returning to the role.
Sarah's travels with the Doctor may have ended, but her story had just
begun...